Firefox: Google Music is still US-only, invite-only, but if you do use the service and wish you could download some of the tracks you've uploaded for offline play or to sync with a mobile device, Google Music Downloader can help.

One of the best things about Google Music is the ability to upload all of your songs, from any computer, to your Google Music account and play them back anywhere. However, the service doesn't make it easy to download your music again later. That's where Google Music Downloader comes in: once installed, click the context-menu for any song in your Google Music library to download it. Keep in mind that the extension is experimental, so your mileage may vary depending on the version of Firefox you're running.

Chrome users should check out Music Plus for Google Music, written by our own Adam Pash, which allows you to download your songs from Google Music, gives you keyboard shortcuts to control playback, supports Last.fm, and more.